The present invention relates to a joint for connection of a metal pipe to gas cock, and more particularly to a joint capable of connecting the metal pipe to a hose fitting of a conventional (old type) gas cock used for fitting the rubber hose.
Heretofore, the gas cock and the gas equipment such as gas range, gas space heater, etc. have been connected to the rubber hose. However, the rubber hose deteriorates in about one year's use and it tends to cause cracks and said cracks tend to give a rise to gas leakage, and also the external pulling force, for example, the force caused by a person who stumbles over the gas hose is applied, the hose is easily pulled out from the hose fitting of the gas cock which also gives a rise to a serious accident.
Under the foregoing circumstances, in recent years, as the pipe for connection of the gas equipment and the gas cock, the metal pipe has become a standard material instead of the rubber hose.
In order to use the metal pipe provided with a coupling at its tip portion, the gas cock of new model adapted for screwing of the coupling is required to be used.
However, in old houses where old type gas cocks with hose fittings are still used, and the hose fitting of the gas cock is formed with several stripes of constricted portions on its outer periphery, and said portions being convenient for gastight connection of the rubber hose to the hose fitting, and therefore it is impossible to connect the coupling of the metal pipe to the hose fitting of the old type gas cock from its structural standpoint. As a result, in the houses where old type gas cocks are installed, the household is compelled to use the rubber hose.
The applicant developed a joint which is capable of connecting the metal pipe to the gas cock of conventional type which is used for fitting the rubber hose in the prior art, but this joint employs rubber or soft material made of synthetic resin in the clamping means for connection of the gas cock of conventional type to the joint, and as a result, this soft material has not only poor clamping force against the hose fitting of the gas cock but also has short service life due to poor durability.